The illumination level of LED or OLED assemblies, e.g. lamps, may be controlled using standard line voltage on/off switches, e.g. by a user switching the line voltage switch on and off according to a given on/off pattern, thereby signaling dimming information to a lamp assembly. The control of the light emission level in the lamp assembly can be done in different ways applying stepwise or continuous dimming to the light source in response to turning the line voltage switch off and on again in a rapid way.
A challenge in implementing a line voltage switch event detection in the lamp assembly is that the function must be performed at a controller of the lamp assembly while no power is available at the line voltage terminals because the line voltage switch is temporarily (e.g. for up to a second) in its off position. An energy storage element may be used to keep a control element of the lamp assembly, i.e. the controller, in operation during this phase. An electrolytic capacitor may be used, which stores sufficient energy to drive the circuits during the time periods where no line voltage power is available.
The use of electrolyte based capacitors, which act as temporary power source for the controller, introduces disadvantages for the LED assembly design, such as long startup times (large capacitance), additional cost (electrolyte based capacitors are expensive to manufacture), additional component size (electrolytic capacitors have a large form factor), and limited lifetime especially at elevated temperatures (electrolytic capacitors dry out).